Key Concepts: The somatic neuromuscular junction is the site of communication between motor neurons and skeletal muscle fibres. Specialisations of the neuromuscular junction mean that activity in and release of transmitter from motor neurons produces contraction of skeletal muscle fibres rapidly and reliably.he neuromuscular junction comprises four cell types: the motor neuron, terminal Schwann cell, skeletal muscle fibre and kranocyte, with the motor neuron and muscle fibre separated by a gap called the synaptic cleft.
Causes. Headaches can be triggered by a variety of factors. The most common cause of headaches is prolonged tension or stress. These are called tension headaches or muscle-contraction headaches. Virtually everyone suffers from this at some time. Muscles in your scalp, neck, and face tighten and contract, causing spasms and pain.
Your headache symptoms can help your doctor determine its cause and the appropriate treatment. Most headaches aren't the result of a serious illness, but some may result from a life-threatening condition requiring emergency care. Headaches are generally classified by cause: Primary headaches A primary headache is caused by overactivity of or problems with pain-sensitive structures in your head.